[68Ga]Ga-SSO120 PET/CT Imaging in Pediatric Patients with Neuroblastoma: Biodistribution and Whole-Body Radiation Dosimetry.

Abstract

The clinical standard for neuroblastoma detection is based on targeting the norepinephrine transporter with [123I]MIBG, which has several challenges. Imaging the somatostatin receptor (SSTR) is a strong alternative. In contrast to standard DOTATATE, SSTR antagonist imaging with [68Ga]Ga-satoreotide trizoxetan ([68Ga]-SSO120) can potentially improve lesion detection as it targets both active and inactive SSTRs. We present the biodistribution and radiation exposure results of [68Ga]Ga-SSO120 PET/CT imaging in pediatric patients with neuroblastoma. Methods: Patients age 3-7 y with stage 4 neuroblastoma received 2 MBq/kg of [68Ga]Ga-SSO120, followed by a 60-min dynamic scan and a static PET/CT scan. SUV normalized to lean body mass (SULmax, SULmean, SULpeak) and time-activity curves were measured for suspected lesions and various tissue compartments. Tumor-to-liver and tumor-to-blood pool ratios were calculated. Radiation doses to various organs and the total-body effective dose were computed. Results: Five patients underwent dynamic [68Ga]Ga-SSO120 PET/CT scanning, with a total of 17 neuroblastoma lesions. The median administered activity was 2.5 MBq/kg (range, 2.1-2.8 MBq/kg). At 60 min postinjection, the median tumor SULmax and SULpeak were 4.28 (range, 1.89-18.07) and 2.71 (range, 1.23-14.77), respectively, and the median tumor-to-liver ratio was 4.05. The highest exposure was in the bladder (22.3 ± 4.3 μSv/MBq). The effective dose was 0.088 ± 0.014 mSv/MBq. Conclusion: [68Ga]Ga-SSO120 PET/CT was safe in pediatric patients with neuroblastoma, with a low effective radiation dose, and detected neuroblastoma lesions with a good target-to-noise ratio. Image acquisition at 30 and 60 min postinjection seemed equivalent.